Slip indicator



v April 9, 1935.

R. F. GOOD SLIP INDICATOR Filed NOV- 17, 1932 l/ Ll T l' H'l I l u I l'I u@ I V INVENTOR l oscof-E 600D BY Q ATTORNEY Patented Apr. 9, 1935 a,188s, as

amended April 30, 1928; 370 O. G. 757) y p This invention relates to adevice for indicating slip, or relative change in rotationalhphase,between a driving and a driven shaft orv between any two coactingrotating. members.

It is the object of this vinvention to provide apparatus of the typespecified that will be simple and cheap to construct, involvepracticallyno expense for upkeep, easy to use and accurate in itsindications. i' 1A With the above and other objects in view,theinvention consistsin the construction, comb-ination and arrangement ofparts as will be described more fully hereinafter.

Inthedrawing: f I I .A Fig. 1 is an axial sectional view on line A-A oflFia-2; i

Fig. 2 is' an elevational VView of the rotating disks, with part of theouter dissout away;

Fig. 3 is a side view of an embodiment having drums'in place of thedisks shown in Fig. l.

It is frequently desirable or necessary to deter-l mine the slip betweena rotating driving element and another element driven thereby through 'abelt or other friction power transmissionk means or by an oil clutch orthe like. In the form of 'my invention for vmeasuring slip shown in Fig.1, the pedestal 4 has journaled in it a hollow shaft 5 lined withantifriction metal 6 within which a second` shaft f1 lis independentlyrotatable, upon which `shafts the pulleys Sand 9 are respectivelysecured and whereby the former shaft may be driven by one ofthe elementswhereof the rotation is to becompared and the lattermay be driven by theother o'f those elements.` Upon shaft 'I isv fixed aj disk Ill uhavingin it radially extendingv slots II. The diskl2 on shaft l5, back ofdisklll,` has in .its face that is-adjacent .disk I0 arcuate grooves I3equal in number to the slots in vdisk Ill.` The grooves I3 are sodisposed that when the projec-l tionof the radially inner end of one ofthe slots II coincides with the corresponding end of a groove, theprojection of Vthe radially outer end of the next slot in advancethereof coincides with the outer end of the saine grooveandare bent witha curvature that constantly increasesl from their inner to their outerendsV whereby, the greater linear speed of the outer portions of thedisk are compensated and the apparent move. ment of the groove alongtheslot is at a constant rate. The grooves I3 ymay be painted in anymanner tomake themreadily visible, ora luminous paint may be usedtherein.r l

It is apparent that if disk vI2 is rotatinguat the same rate as adriving shaft anddisk Ill at the Y same rate as a shaft driven therebyand there is slots, it will have moved from the innerfend of theYpositionsuchas the uppermost one, and it is'not no slippage betweenthem and the two disks had 1 the `relative positions yas shown in FignZ,they would remain without change in thatposition with a portion ofagroove showing atthe extreme end portions of Aeach of the slots II. Onthe 4other hand, if disk. I0 is rotating faster than'disk I2. the.portion of the groove seen through a slot willmove successively fartherout radially until .z ywhen the former disk'has gained uponthe latter jan angle equal to the anglebetween two adjacent slotgto the outerendthereof. If disk I2 is rotating .the faster, the apparent movement ofthevisible portion of the groove will be inthe .opposite I:

direction. It is to be noted that the number of slots 1 should not be sogreat that persistence Aof 4vision y .will prevent distinguishing one`slot from another."

The number` of complete transits of a slot over a groove during-a giventime interval divided by the number of slots gives the differenceinrevolutions during that interval between the elements whosevratesarebeing compared. Since all'the slots` have thevsarnerelativepvosition with respectr to the grooves, it is necessary towatch-'but one -i required that any individual slot be followed Vby theeye. f ,InFig. 3 the inner/drum I9 is fixed on shaft I4 to rotatetherewith Vandhas on its outer. surl face diagonal'grooves I5 paintedwhite or with luminous paint asinv the case of grooves fIS in disk I2.The memberIB is connected tov ay ,torsional-f vibration damping couplingdevice through which power is Vtransmitted to shaft "I4 and which isfree to rotate withvrespect to shaft I4. This particular-.type ofcoupling-rel quires a certain degree of slippage betweenthe drivingshaft to whichmember I6 is connected and the shaft I4, and for efiicientoperation* this slippage must beraccurately controlled. In'. fact,serious damage to the shaft willresultlif the slippage dropsto zero.ASecured to member .I6 is yan outer drum I1 having in itslots I8`disposed parallel to the shaft I 4 and spaced apart; .45 .a planevperpendicular to shaft I4, subten'dedjby an angular distance equal tothe angle, taken.in1

amgroove 4 I5. It is apparent thatslippage of memberv I6 with respect toshaft I4 will bein-1A l dicated by transit of slots I8 overgrooves I5,thequ .1f magnitude ofr such slippage perunit offtime be-l-.iv 50v .ingkdetermined asin the'case ofthe modiiica-` tion of my invention usingvthe-disks.

lIt; win be unaerstoodthat the above descrip-"f` tion and vlaccompanying Vdrawing comprehend f only the generalandpreferredembodiment of 55,111.7'.

struction, proportion and arrangement of parts may be `made withinthescope of the appended -claims without sacrificing any of the advantages`Vof this invention. f i u The invention described hereinmay be Amanu- 1faetured andgpuvsedby or for L,the Government-of the United ,State'slJorgovernmental' purposes withoutk the payment ofA any royalty thereon.` 1o

' connection inherently providing.jfpr` slippageher;`

tween .saidv'shafta a drumlmounted on said driven vshaftand a seconddrum`v` mounted" on=an""ele a ,ment fof said connection, said drumsbcingfon-vcentric and disposed oneinside the otherfthe and par`allel tothe said inner one of said drums having on it a plurality of equallyspaced, self-luminous, readily visible diagonal markings and the outerone of said drumsfhaving in it a plurality of slots parallel to the axisof said shaft through which said markings may be seen, said slotsbeingequally spaced andequal in number ato,` said: markings,

thesaid slotstrans'iting `said markings when said drums are rotating atdiierent speeds, said f-.-ii;'markings being so disposed that the`adjacent Y Means for measuring slippage between adriv-fing shaft and ashaft driven thereby rthreugh a ends of -two consecutive markingsliesubstantialangular distance equal to that between the lines drawn'through the endsof one of said markings axis.

ROSCOE F. GOOD.

-ly onVthe same line parallel to the axis of the `shaft and the saidslots-being spaced apart any

